Cylindrical cutter head with slotted blade seat



1955 J. 5. BALLANTINE CYLINDRICAL CUTTER HEAD WITH SLOTTED BLADE SEATFiled May 17, 1.949

2 Sheets-Sheet l Feb. 15, 1955 J, 5. BALLANTINE 2,702,059

CYLINDRICAL CUTTER HEAD WITH SLOTTED BLADE SEAT Filed May 17, 1949 2Sheets-Sheet 2 United States Patent CYLINDRICAL CUTTER HEAD WITH SLOTTEDBLADE SEAT James S. Ballantine, Absecon, N. J. Application May 17, 1949,Serial No. 93,701 2 Claims. (Cl. 144230) This invention relates torotary cutter heads of the type employed in jointers, planers andsimilar woodworking tools and more particularly to improved mounting andholding devices for the bits or cutter blades of rotary cutter heads.

A primary object of the invention is the provision of improved adjustingand holding devices for the bits or cutter blades of a rotary cutterhead wherein the bits or blades may be adjusted to a desired cuttingposition and then quickly and easily secured in such position by asimple manipulative procedure.

' Another object ofthe invention is the provision of improved holdingdevices for the cutter blades of rotary cutter heads which may bequickly and easily released from locking position.

A further object of the invention is to secure a cutter blade in arecess of converging cross-section in a rotary cutter head by a lockingbar through wedging or clamping engagement of one side of the bar with aside wall of the recess limited to substantially line engagementlengthwise of such sides. A related object of the invention is todifferentially shape the coacting sides of the recess and bar andthrough such shaping limit their engagement to substantially lineengagement.

Other objects and advantages of the invention will become more apparentin connection with the following description of preferred embodiments ofthe invention illustrated in the accompanying drawings.

In the drawings:

Fig. l is a view in side elevation of a rotary cutter head embodying oneform of the invention;

Fig. 2 is an enlarged view in side elevation of a portion of the cutterhead shown in Fig. 1;

Fig. 3 is an enlarged view similar to Fig. 2 with the cutter blade,locking bar, and adjusting screw omitted from the lower slot;

7 Fig. 4 is a cross-sectional view taken on the line 4-4 of Fig. 2;

Fig. 5 is a perspective view of the locking bar;

5 Fig. 6 is a vertical cross-sectional view of the locking Fig. 7 is avertical cross-sectional view of a modified form of locking bar; and, I

Fig. 8 is a vertical cross-sectional view of a further modified form oflocking bar.

In general the present invention is directed to novel means forremovably securing the cutter blades of a cutter head in place. Thesecuring means includes a locking bar. The locking bar together with thecutter blade is fitted in a recess of outwardly convergingcrosssectionin the cutter head.

' Thecutter blade will be disposed with one side against oneside, of therecess. The locking bar will be removably located between the blade andthe opposite side of the recess. The bar should be of a cross-section tobe loose'in the inner wider portion of the outwardly converging recessbut movable outwardly as a Wedge into bearing engagement at its oppositesides with the cutter blade and one side of the recess.

- The coacting sides of the recess and locking bar are limited tosubstantially line bearing engagement lengthwise thereof at anintermediate area of the bar when the bar is in wedging position. .Tothis end such sides aredifferentially shaped so as to be spaced fromeach other above and below their line of engagement. One or the other ofsuch sides must be contoured vertically, and both may be. I prefer. tocontour one only of the coacting sidesandtomake the other flat. Ifurther prefer to contour the side of the locking bar and to make thecoacting side of the recess fiat and I have chosen various embodimentsof such form of the invention for illustration in the drawings;

T IThe' opposite side 'Ofthe" locking bar is preferably flat so as tomake extended surface contact with the side of the cutter blade andwedge it securely against the second wall of the cutter head recess.

The shaping of the cutter head recess and locking bar as above explainedto limit their sides to substantially line engagement insures increasedwedging action and permits easier manipulation of the bar to and fromwedging position than would be the case if the coacting sides of therecess and bar were both flat and in bearing engagement over an extendedsurface area.

While operation tests have shown that centrifugal force developed byrotation of the cutter is suilicient to maintain the wedging action ofthe locking bar it is desirable to provide means for positively holdingthe bar in wedging position and which also serves to adjust the bar fromreleased to wedging position. Such means preferably will comprise aseries of set screws threaded vertically in the locking bar which willbear at their inner ends against the bottom of the cutter blade recessand which upon turning will move the bar outwardly in the recess untilit reaches wedging position.

Contouring to obtain the desired line contact between the sides of thelocking bar and cutter blade recess may take a number of forms.According to one type of construction the side of the locking bar whichengages a flat-formed side of the recess is formed with two angularlyrelated upper and lower surfaces or faces which meet along alongitudinal line substantially midway between the top and bottom of thelocking bar. The sur face below the line may desirably be flat and ispreferably substantially parallel to the opposite blade-engaging side soas to be downwardly divergent at a small acute angle with respect to theadjacent coacting side of the recess when the bar occupies its wedgingposition therein. The surafce or face above the line is inclinedinwardly toward the opposite side of the locking bar with a curvedcontour so that when occupying its normal position in the recess it willform a gradually increasing small acute angle with the adjacent side ofthe recess from the line of intersection With the lower surface.

In another but similar type of construction the recess coacting side ofthe locking bar is contoured to provide upper and lower surfaces orfaces which are both flat and angularly related so as to meet along alongitudinal line and form small acute angles with the adjacent side,again flat, of the recess. In still another type of construction theside of the locking bar may continuously be curved for all or asubstantial intermediate part of its height so that an intermediatecurved portion is tangent to the adjacent side of the fiat form of therecess and adapted to bearing engagement therewith substantially along alongitudinal line and the portions of'the side above and below thetangent portion curve away from v the adjacent face of the recess toform gradually increasing acute angles.

These and similar types of construction resulting in substantially linecontact between the locking bar and the adjacent wall of the recess maybe utilized in accorddance with the present invention. The expressionline contact? as used herein is intended to mean contact along a line orarea of very narrow width longitudinally of the locking bar ascontrasted to extended surface contactl between substantially parallelflat faces as hitherto use Referring now to the drawings andparticularly to Figs. 1-4 the numeral 9 designates a cutter head ofiron, steel, or the like, comprising a body member 10 which may besubstantially cylindrical in shape and formed with a plurality oflongitudinal recesses or channels 11 for the reception of cutting blades12 and locking bars 13. Any suitable number of recesses may be used,four being shown for the purpose of exemplifying the invention.

Each of the recesses 11 has a mouth 14 opening toward the periphery ofthe cutter head, opposite side walls 15 and 16 and a bottom wall 17. Theside wall 15 forms a backing-face against which the impact of the blowexerted on the blade 12 in the cutting operation is received. The bottomwall 17 preferably extends at an acute angle with relation to the sidewall 15 and is provided at one edge thereof with a groove 18 for thereception of the inner edge of blade 12. The side wall leisarranged. in.outwardly .convergingrelationship. .with.

the side wall to form a.-recess which is of tapering form incross-section, wider at its bottom area than at its mouths. V p

Each'of the? locking barsr13.has. a side: face 21). adapted to be urgedtoward theblade 'an opposite: side-face 21-, atop -face .22, and abottom face 23. In. operative position the'side face is substantiallyparallel to thebacking-faee 15 of the recess 11 and. isdesigned'towedgethe blade in. adjusted position aswill be'apparentfrom FiguA. The bottomface; 23 :iskpreferably, thou gh. not necessarily, arrangedsubstantiallyat'right angles to the side face 20and at an acute angle to. the bottomwall 17 of the recess 11. The-top face 22 is preferably concavely curvedor grooved as shown at 37 to provide a chip clearance and therebyincrease the. depth 0f; cut of the machine; V

The side-face 21 of thelockingybar'is' shaped'so: that the locking;barwill have a wedge-action within the walled :recess :11. In-accordancewith the. present invention this;wedge action is. along-a single line oficontact-atdthemeeting of .two angularly relatedupper andlowersurfaces'of the side face-21'. This construction facilitates andincreases the wedging:actionzof1the1ockingrbar and additionallyfacilitatespremoval of 'the locking, bar from its wedging. position.

In the form of the invention .shown int-Figs. 1-6' the sideface 21 isformed with two:angularlyrelatedxsurfaces 24 and '25 which meet orintersect along a line 26 extending longitudinallyiof the bar. The.surface 24'is preferably flat and may desirably be substantiallyparallel with the opposite side facer20.. The surface is preferablycurved convexly inwardlyjtoward the face 20. in'such' a: manner that noportion of' the curved surface-above. the line 261 is incontact with theside wall 16 of the recess 11 .When the locking bar 13' is inwedging'position. This construction provides an improved wedge actionalong a relatively narrow line of contact and simultaneously minimizesthepossibility of particleswof wood and the like working aroundthe-locking bar to disturb the wedging action. In-the:modification ofthe invention shown-in-Fig. 7 the side face 21 is preferably formed withtwo intersecting'flat faces 27 and 281wh-ich'meet in a line29extendingvlon'gitudinally of the locking bar. The faces. 27 and 28 fare preferably arranged so that they form small acute angles withtheside wall 16 of the recess-11 thus giving the desired'line contact andminimizing the collection :of foreign matter.

A further modification of the locking bar is shown inFig. .8 wherein theline contact'is-obtained by a curved face 30 whichv is shaped sothata-portion thereof is tangent to the wall 16 along a line longitudinallythereof; The curve of the face30 maybe variedas-desiredbut'isipreferably arrangedso as to recede gradually and to axrelativelylimited extent away from the face 16 above and below the line ofcontact.

In accordance with the present invention the line-of contact ofthelocking bar withithe adjacent wall of the recess is preferably locatedapproximately midway between. th'eupper and lower edges of the face 21.in order to obtain best allaround results. Quite satisfactory re= sultsmay be obtained, however, when the line, of contact is' above or belowthis location ZS'IOIlgi as thev resultant of the forces acting onthe-blade througlr'the line contact are sufficient to. exertthedesired'clamping action.

The locking bars 13are moved to and released from locking position byset-screws 31; Set-screws 31'. are screw-threadedlymountedrin openings32in. the'locking bars 13- and are'preferably'disposed substantially atright an'glesto the lower wall 17 0f the recesses. The topsof theset-screws may be provided with suitable slots or the like forengagementby' a screw driver; wrench or other suitable tool to rotatethem. When it is desired to move the locking bars .to locking-positionthe set-screws 31 are rotated until they contact thebottom walls=17 ofthe: recesses 11. Furtherrotation of' the set-screws urges the. lockingbars upwardly in the tapering recesses-11 s01 thatith'e line contactbetween-the side faces-21 of the locking bars andthe adjacent walls1'6ofthe recesses urges-"the-faccs 20*of thelo'cking-ibarsinto tightengagementwitli-the cutting:blades123 The blades'1'2 areithus clampedbetween'the'walls 15 of'the' recesses 11 an'dthe faces. 20.. of.the.1ocking. bars, 13.. andusecurely, held..in. position for the cuttingoperation.

Prior to being clamped in position as above described the cutting blades12 are adjustably positioned for a desired cutting operation by nuts 33screw-threadedly engaged with-set-screws; 34. Set-screws-34are'rotatably mounted in openings 35 in the cutter head 10 with thebottoms thereof resting in contact withv the bottoms of the openings.The tops of the set-screws 34 may be provided with slots or the likewhereby they may berotated by a suitable tool to raiseor lower thenuts33. The nuts 33 are provided with extensions 33a which underlie thelower edges of the cutting blades 12 so as'to support-and move them'upwardly or downwardly iii responseto ro tation of the set-screws 34.The-extensions 33iz-move upwardly and downwardlyin-openings-36:-whiehare par allel to and communicate with openings 35.lift-W111? be apparent that *when the-set-screws 34 arexrotated' with'the bottomsthereof in contact with-the bottomsof the openings 35 thenuts 33 being screw-threadedly-engaged there= with and held againstrotation: thereon" are moved-upwardly or downwardly to adjustablypositionthewutter blades 12. When the blades aeethus adjusted' to-adesir'ed 'cuttingposition the locking bars may then be moved to lockingposition asabove described-Eta securely 'h'old the cutter blades inposition.

It will thus be seen thatthe. present invention pro vides an improvedcutter head 'wherein' the cutter-"blades may be easily, quickly; andaccurately adjusted-to-a desired cutting position andthen'quickly'and'positively cladmped -in such-position-by a: simple 'manipulative=pro= ceure.

Although I have illustrated-z and'dcscribed: preferred embodiments ofthe invention-'Ido not'intend' to be limitedto the'precise detailsthereofas the scope of the invention is best defined in the appendedclaims.

I claim;

1. A rotary cutter comprising a body member having alongitudinal slottherein provided with outwardly goon: verging walls, a cutter blade inthe slot. a locking barin the slot, means for adjustably positioningsaidlocking bar outwardly 'of the. slot so that one face thereofisinpressure contact with the cutter blade andthe opposite face thereof isin pressure contact with. anaadjacentiwall of .the slot, said oppositeface of the locking banirlcl'ud mg a longitudinally straight and"vertically convexly rounded surface in contact with said adjacent .wallalong, a. line extending longitudinally thereof, and spacedlffomsaid'wall above and below this line, saidloc-kingt-bal: being narrowerat its. top than at its bottom-.andithe surfaceofsaid oppositefaceadj'acentthe. top converging in an upward direction towards said oneface.

2. .A rotary cut-tercomprisinga body member having a longitudinal slottherein providediwithoutwardly' con-1 verging walls, a cutterbladeinthe'slot, a. locking bar; in the slot, means for adjustablypositioning.saidrlocking baroutwardly of the slot so that one. facethereof isz-in pressure contact with thecutter blade and the. oppositeface th'ereofis in .pressurecontact withan adjacentjwall of the slot,said opposite face .ofthe: lockingbar having a, convexly. curved.surface portion andwaaffl'at surface portionwhich'meet along alineextending longitudinally thereof, .saidsurfaceportions being: incontact with-said adjacent wall along theircommon meeting-lineandsbeingspacedi therefrom above andbelow said meeting; line, said locking barbeing-narrower'at itstop thanat its bottom and the surface ofsaid-opposite face. adjacent the top, converging in an upwarddirectiontowardssaid one face.

References Cited in the file ofthis patent-- UNITED STATES PATENTS874,871 Shimer' Dec; 24, 1907 995,024 Mitchell June13; 1911: 1,032,636Watkins July 1:6, 1912- 1,039,054 Hartzell Sept. 17, 1912 1,320,482Lenker Novmi'; 1919 -1,780;846.- Shimerzret al Nov. 4," 1930 FOREIGNPATENTS.

93,153" Sweden 1938: 550,077 Great Britain ....D'ec.'l 22,. 1942 890,658France Feb. 14, 1944

